Dry shaver cutter head



Aug. 19, 1941.

R. KNAPP DRY SHAVER GUTTER HEAD Filed Nov. 6, 1937 2 Sheets-Sheet 1 Aug. 19, 1941. R. KNAPP 2,253,037

f rmmf sHAvER CUTTER HEAD Filed Nov. v6, 1937 2 Sheets-Sheet 2 Patented Aug. 19, 1941 DRY sHAvER CUTTER HEAD Raymond Knapp, Long Island City, N. Y., assignor to Knapp-Monarch Company, St. Louis, Mo., a corporation of Missouri Application November 6, 1937, Serial No. 173,104

16 Claims.

An object of my present invention is to provide a hair clipper which can be inexpensively manufactured and parts thereof readily assembled to provide a complete cutter head or hair clipper assembly, the device being intended primarily for clipping hair on the face and therefore used in connection with a clipper of the type commonly termed a dry sliaver and the present application being a continuation in part of my copending application, Serial No. 131,149, led March 16, 1937.

Another object of my invention is to provide a cutter head assembly Iin which the inner and outer cutters consist of relatively thin plates of spring steel or the like formed to the desired shape, the outer cutter plate being eiectively reinforced by' a plurality of relatively thi-ck plates or blocks of metal which, together with the thin plate form the outer cutter, all the plates being riveted together to thereby form a rigid outer cutter unit.

Another object is to form the outer plate substantially U-shape, preferably with the corners of the U displaced beyond the planes of the Iarms thereof and the plate being slotted across the projecting corners which give la comb action during shaving operations to pick up the hair preparatory to clipping it. y

Another object is to provide an inner cutter formed of a plate of metal shaped to fit the inside of the outer cutter plate or which has at least the teeth portion thereof fitting the teeth portion of the outer cutter plate, the shape of the inner cutter being comparatively open so that la cleaner (brush orthe like) can be inserted therethrough and will readily clean out hair without necessitating disassembly of the cutters. cilitates removing the hair by blowing therethrough and minimizes the possibility of clogging because the hair clippings can readily fall or be jarred out during operation.

Still another object is to provide an inn-er cut- 'ter which has teeth spaced sufliciently far enough apart to prevent clogging thereof With waste skin tissue or seba'ceous material during operation.

A further object is to provide a dry shaver cutter head which may be operated with a maximum of efliciency and a minimum of friction made possible by the use of a novel biasing means for the inner cutter to resiliently cause the clipper teeth thereof to maintain shearing contact with the clipper teeth of the outer cutter and the mechanism therefor consisting of The open center construction also faslidlable and oscillatable rods contacting with the inner cutter and spring urged into such contact, the oscillat-able feature of the rods permitting them to oscillate with the sliding movement of the inner cutter so that friction between the rod and the inner cutter is eliminated.

A further object is to provide an outer cutter which includes a shear plate that can be formed inexpensively of sheet metal bent substantially U-shlape and having its end edges roll-ed to reinforce the plate and at the same time provide an edge for the cutter head which prevents gouging of the cutter head into the skin of the user.

Still a further object is to provide the outer cutter plate with a centrally located rib which serves as a reinforcement for the bottom p-art of the plate where it engages the face during hair clipping operations, the inn-er cutter being formed with an open center to clear the rib.

Still a further object is to provide an inner cutter which is formed of sheet steel or the like and which can be formed in a number of different shapes yet accomplish the same result of rigidity against torsional strains and pressure on the shearing teeth thereof, the inner cutter being capable of actuation by an actuating element of a. dry shaver motor or the like.

With the foregoing and other objects in view, as will become evident as the description of my cutter head proceeds, my invention consists in the construction, arrangement and combination of the various parts thereof whereby the contemplated objects are attained as set forth in my specication, pointed out by my claims and illustrated in my drawings. With speciiic reference to the various views in the drawings:

Figure 1 is an enlarged sectional view through a dry shaver cutter head embodying my invention and -showing the cutter head assembly mounted in a dry shaver casing.

Figure 2 is a side elevational view of the cutter head assembly, parts thereof being broken away and other parts being shown in section to illustrate details of construction.

Figure 3 is a plan elevational view of the inner cutter.

Figure 4 is an enlarged sectional view on the line 4-4 of Figure 2.

Figure 5 is an enlarged sectional view on the line 5 5 of Figure 2.

Figure 6 is a perspective view of the inner and outer cutters with the ends thereof cut off and shown in section: and

^ flanges which are indicated at 22e.

Figures '7, 8, 9 and 10 are sectional views as taken on the line 1-1 of Figure 2, showing modified shapes of the inner and outer cutters.

On the accompanying drawings I have used the reference numeral I to indicate a dry shaver motor housing. A cutter head reception member I2 is mounted in theend of the motor housing for receiving the cutter head assembly indicated generally as H. The usualy dry shaver includes an actuating arm or the like I3. By way of illustration, the arm I3 is shown as being pivoted on a shouldered screw I4 so that it may be oscillated by the dry shaver motor (not shown). 'I'he screw I4 is supported by a bracket plate I5 and a spring clip I6 serves the purpose sition relative to the dry shaver motor housing.

My improveddry shaver cutter head assembly H comprises a plate I'I bent substantially U-shape and serving as an outer cutter, the arms of the plate I'l vbeing indicated at I1a. These arms have diverging portions IIb and a bottom cross member or connecting portion I'Ic. The plate arms Ila are spaced by a pair of relatively thick plates I8, while outside the arms relatively thick plates I9 are provided. The arms Ila and the plates I8 and I9 are held rigidly assembled relative to each other as by rivets 2'0. Two of the plates I8 are provided longitudinally spaced from each other with a space 2l between them for the actuating arm I3. Notches I'Id are provided in the plate I1 and extend across the bends thereof between the diverging portions Ilb and the connecting portion IIc. These provide spaced clipper teeth for the outer cutter and, due to the diverging character of the portions Ilb, provide comb-like teeth to pick up the Ihair as the cutter `of retaining the cutter head H normally in pohead is moved across the face of the user so as to facilitate clipping of the hair by the cutter head.

An inner cutter is provided which is also formed of a plate of sheet spring steel or the like. This plate is indicated generally at 22 and includes a back 22a. The back 22a has a perforation 23 therein into which the actuating arm I3 extends with the arm substantially spanning the perforation longitudinally of the back 22a. Thus, when the arm I 3 oscillates, it will impart to the plate 22 reciprocating motion relative to the plate I'l. The plate 22 further includes side flanges 22h which preferably are shaped to follow and contact with the portions I'lb of the plate I'l. The terminal edges of the plate 22' extend toward each other in substantially the same plane and in the form of The side fianges 22h adjacent the lower edges thereof and the flanges 22e are notched as indicated at 22d to provide clipper teeth to coact with the teeth of the plate I'I. The teeth of the inner cutter are spaced relatively farther apart than those of the outer cutter. 'I'he outer cutter teeth are close together so that they can receive a maximum number of hairs. After the hairs are cut off, they would have a tendency to clog the teeth of the inner cutter if they were likewise closely spaced. To eliminate this trouble, I space the teeth of the inner cutter so that there is at least .025 of an inch open space between them. I have found a space of this extent to be suicient to prevent clogging of the inner teeth with hair, waste-skin tissue and sebaceous material during operation. In actual practice I iind -that the relative spacing between the inner and outer teeth if arranged in a ratio of one to two, works satisfactorily.

` v The connecting portion I1c of the plate I1 is provided along its center with a rib. 24, the notches I 'ld terminating short Aof the rib 24. The inner cutter plate 22 has its flanges 22C also terminating short of the rib 24 s0 as to clear it. The rib 24 serves as a reinforcement against bending or inward bowing of the relatively thin connecting portion I1c of the plate I'I which in actual practice is slightly thinner than the remaining portion of the plate due to a lapping operation of the innerand outer cutters to secure accurate fitting of the inner and outer cutter teeth together in shearing 'relationship to each other.

By constructing the outer cutter of the plate I1 as disclosed, I am able to use a comparatively thin plate so that the hair on the face can be clipped quite close to the skin, yet due to a number of features already described, the relatively thin plate is amply reinforced against any undesirable distortion during use. These features specifically consist in reinforcement by the plates I8 and I9, the diverging arrangement of the portions Ilb of the plate I1 and the reinforcing rib 24. The plate I1 is further reinforced by rolling the end edges thereof as indicated at 25. The rolled edges 25 extend throughout the extent of the ends of the plate and along the connecting portion llc thereof, which construction serves as a protection against gouging of the edge of the plate into the skin of the user while using the cutter head.

Although I have shown the inner and outer cutters as being of one shape in Figures 1, 5 and 6, they may be formed in other shapes as illustrated in Figures 7, 8, 9 and l0. The shape in Figure 'l is similar to that in Figure 1 with the exception that the diverging portions of the plate I1 are of a different angle and of less extent as indicated at I'Ib'. The .bead of the outer cutter indicated at 24 is of greater extent while the inner cutter plate has substantially parallel side flanges 22h and the anges 22o. thereof extend away from each other instead of toward each other. The inner cutter ls substantially centered by the bead 24. The other elements of Figure 7 are similar to those of Figure 1 and accordingly bear the same reference characters.

Referring to Figure 8 the bead 24"`is of less extent than illustrated in Figure 1, While the sides 22h of the inner cutter converge downwardly instead of being parallel to each other.

In Figure 9'the converging side flanges 22b" are connected together as by rivets 26. The inner cutter in this figure is illustrated as being made of substantially thinner metal and the rivets 26 connecting the sides thereof together serve the purpose of permitting one side to reinforce the other.

In Figure 10 the arms Ila' are substantially parallel throughout their extent and the connecting portion Ilc of the outer cutter I1" omits the bead 24. The inner cutter is substantially rectangular in shape and the side flanges 22h' thereof are rigidly connected together as by shouldered rivets 26. The various modifications of the inner and outer cutter plates may be carried out as suggested yet the various advantages due to the construction in general of the cutter head assembly is retained with the various forms of Acutter illustrated. The several shapes of outer cutter I1', I1", I'I" and I1"" are illustrated respectively in Figures '7, 8, 9 and 10.

It has been customary to urge the inner cutter into shearing contact with the outer cutter by means of spring-pressed balls engaging the inner cutter, such balls necessarily imposing a certain amount of friction to resist free movement of the inner cutter relative to the outer cutter. I provide a means which urges the teeth into shearing contact yet minimizes the degree of friction involved. My mechanism for accom:J

plishing this result consists of a pair 01' rods 21, slidably and oscillatably mounted relative to sleeve nuts 28. The sleeve nuts 28 are mounted in the'plates I8 which are cut away so as to provide spaces 29 in which the rods .21. may oscillate (seefFigures 2 and 4). Springs. are mounted on the rods 21 and are interposed between the nuts 28 and rounded heads 3l on the lower ends of the rods 21. The rounded heads 3| contact with the back 22a of the inner cutter to urge the teeth thereof into shearing contact with the teeth of the outer cutter. The rods 21 are provided with enlargements or heads 32 which, when ,the inner cutter is assembled in the outer cutter, are slightly spaced from the nuts 28 so that the springs 30 are free to act. -When the inner cutter is removed from the outer cutter, however, these heads limit sliding movement of the rod 21 inwardly so that they do not become displaced and are in position to properly coact with the inner cutter after it is assembled in the outer cutter. In operation the-rods 21 will oscillate inasmuch as enlarged or tapered bores 33 are provided in the nuts 28. In Figure 2 the inner cutter is illustrated as being moved slightly to the right of a central position and the rods 21 as swung slightly toward the 4right to illustrate the action thereof. As the movement of the inner cutter is slight, it is obvious that the oscillating movement of the rods 21 will also be slight and their sliding movement relative to the nuts 28 practically negligible. This results in reduction of friction to a minimum yet effective biasing of the inner cutter to shearing contact with the outer cutter is secured.

Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and 4purpose of my invention, and it is my intention to cover by my claims, any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

I claim as my invention:

1. In a dry shaver cutter head, an outer cutter and an inner cutter, said outer cutter comprising `a plate of uniform thickness bent substantially U-shape, means for rigidly connecting the arms thereof in spaced relation to each other, said plate, across the bends thereof, having notches formed therein whereby to provide cutter teeth to coact with said inner cutter, and an imperforate rib formed along the center of the connecting portion of said U-shaped plate of metal having the same thickness as the plate, said teeth terminating short of said rib.

2. In a dry shaver cutter head, an outer cutter and aninner cutter, said outer cutter comprising a plate bent substantially U-shape, means for rigidly connecting the arms thereof in spaced relation to each other, said plate across the bends thereof having notches providing cutter teeth to coact with said inner cutter, and an inwardly directed bend extending longitudinally along the cross member of said U-shaped plate forming a rib, said rib being centrally located and projected toward the inner cutter a distance not greater than the thickness of the inner cutterand said inner cutter being formed to receive said rib.

3. In a dry shaver cutter head, an outer cutter and an inner cutter, said outer cutter comprising a plate bent substantially U-shape, means for rigidly connecting the arms thereof together, said plate across the bends thereof having notches formed therein whereby to provide cutter teeth Ato coact with said inner cutter, an inwardly directed bend extending longitudinally along the cross member of said U-shaped plate forming a rib, said teeth terminating short of said rib, said rib projecting toward the inner cutter a distance substantially equal to the thickness of the plate and said inner cutter having an open-center receiving said rib.

4. In a dry shaver cutter head, an outer cutter and an inner cutter, said outer cutter comprising a plate of substantially U-shape, said plate having notches formed therein whereby to provide cutter teeth to coact with said inner cutter, said inner cutter comprising a plate having a back, a pair of side flanges and a pair of terminal end iianges extending toward each other, said end flanges having notches formed therein to provide teeth to coact with the teeth of said outer cutter, said end iianges terminating spaced from each other to provide a space therebetween and a rib formed on said U-shaped plate and located between said end flanges when the inner cutter is assembled relative to the outer cutter.

5. In a dry shaver cutter head, an outer cutter and an inner cutter, said outer cutter comprising a plate of substantially U-shape, means for connecting the arms thereof together in spaced relation to each other, said plate having notches formed therein whereby to provide cutter teeth to coact with said inner cutter, said inner cutter comprising a plate having a back, a pair of side flanges and a pair of terminal coplanar end flanges, said end flanges having notches formed therein to provide teeth to coact with the teeth of said outer cutter, said end anges terminating spaced from each other to provide a space therebetween and a rib formed on said U-shaped plate and located between said end flanges when the inner cutter is assembled relative to the outer cutter.

6. In a dry shaver cutter head, an outer cutter and an inner cutter, said outer cutter comprising a plate bent substantially U-shape, said plate having notches formed therein to provide cutter teeth to coact with said inner cutter, said inner cutter comprising a plate bent to form a back and a pair of side anges bent downwardly therefrom, the lower ends of said side flanges being brought into contact with each other adjacent the cutting edge and being bent outward from the area of contact to diverge from each other and notches therein to provide teeth for cooperation with the teeth of the outer cutter.

7. A dry shaver cutter head assembly comprising an outer cutter and an inner cutter, said outer cutter comprising a plate bentU-shaped. the bends between the cross member and the arms of said U-shaped plate being displaced outwardly so that the axes of said projected bends lie in the direction of travel of the inner cutter, beyond the planes of the arms of the plate, slots in said U-shaped plate, said inner cutter comprising a plate bent to form a back and a pair of terminal anges coacting with the cross member of said outer cutter, said terminal iianges being bent outwardly from the center and having slots therein to form teeth, and an inwardly projecting portion on the outer cutter intering a pair of headed rods secured one in each of said apertures slidable and swingable relative to said outer'cutter and carried by said head assembly, the heads of said rods engaging the inner cutter, anda spring surrounding each rod' carried by the head assemblyhaving ends interposed between the head thereof and the outer cutter to urge the inner cutter toward shearing contact therewith, said rod having an enlargement positioned externally with respect to the aperture to limit sliding movement of the rod toward the inner cutter, said enlargement, when the inner cutter is within the outer cutter, be-

ing spaced from the outer cutter.

9. In a dry shaver cutting head assembly an outer cutter having a slotted closed outer end portion providing cutter teeth and an inner cutter comprising relatively thin sheet material spread to a fiat surface at the inside face, provided with complementary side portions extending side by side to the outside face and in contact with each other at a point adjacent said outside face and secured to each other in the form of a reenforcing plate, and an outside portion for the inner cutter extending outwardly from the plate provided with slots forming teeth therein cooperable with the teeth in the outer `cutter to provide a shearing action therebetween.

10. In a dry shaver cutter head, an outer cutter and an inner cutter,` said outer cutter comprising a platel of substantially U-shape, said plate having notches formed therein whereby to provide cutter teeth to coact with said inner cutter and a longitudinal inwardly extending rib on the face thereof, said inner cutter comprising a plate having a back, a lpair of side fianges and a pair of terminal end flanges extending toward each other, said end flanges having notches formed therein to provide teeth to coact with the .teeth of said outer cutter, the notches in said end flanges having a shape and dimension adapted to admit the positioning of said rib in contact therewith to guide the action of said inner cutter when the inner cutter is assembled relative to the outer cutter.

11. A hair clipper comprising two spaced plate sections formed of sheet metal having their end portions bent outwardly and then inwardly toward each other to form a flat skin contacting `surface and separated from each other [by a longitudinal extending imperforate rib, a spacer between said plate sections, means for securing said spacer and plate sections together, slots in said plate sections extending through and transversely of the outer bends exclusive of the rib, and a movable cutter within the plates provided with spaced teeth on opposite sides of the rib making shearing contact with the slotted portions of the plates on the flat face only thereof `and means for reciprocating the cutter.

12. In a dry shaver cutter head, an outer cutter and an inner cutter, said outer cutter .comprising a plate of substantially U-shape, said plate having notches formed therein whereby to. provide cutter teeth to coact with said inner cutter, said -inner cutter comprising a plate having a back, sides and a pair of terminal end flanges spaced one from the other on each side of the center, said end flanges having notches formed therein to provide teeth to coact with the teeth of said outer cutter, and a rib impressed inwardly on the surface of said U-shape plate and located between said end flanges when the inner cutter is assembled relative to the outer cutwhereby to provide cutter teeth to coact with said inner cutter, said inner cutter having shearing portions in contact with the outer cutter and spaced from lthe interior of said rounded corners, the rounded notched corners of the U- shaped plate providing thereby a comb-like action during operation free from the inner cutter.

14. In a dry shaver cutter head, an outer cutter and an inner cutter, said outer cutter comprising a plate bent substantially U-shape with rounded bends at the corners thereof projecting a substantial distance outward beyond the walls to give a comb-like action during operation, a spacer between the arms thereof, means for securing said arms to said spacer, said plate having notches formed therein across said rounded bends from one side to the other whereby to provide continuous cutter teeth, said inner cutter having shearing portions in contact with the flat inner side of the outer cutter only and spaced from the rounded bends.

15. In a dry shaver cutter head, an outer cutter and Van inner cutter, said outer cutter comprising a plate bent substantially U-shape and having notches formed therein whereby to provide cutter teeth to coact with said inner cutter, and an imperforate reenforcing rib comprising a central portion of the outer plate of uniform thickness throughout substantially equal in thickness to said plate, bent inwardly from the face of said outer plate.

16. In a dry shaver cutter head, an outer cutter and an inner cutter, said outer cutter comprising `a plate of substantially U-shape, said plate having notches formed across the corners thereof, whereby to provide cutter teeth at the closed portion of the U-shape to coact with said inner cutter, said inner cutter comprising a plate formed with a back and a pair of side iianges extending downwardly therefrom, the lower ends thereof being bent so that lthe outer surfaces thereof lie in substantially the same plane and wherein said plane is parallel to and in contact with the inside surface of the closed portion of the U-shaped outer cutter, said inner cutter having notches to provide teeth for cooperation with the teeth in the said U-shaped plate.

RAYMOND KNAPP. 

